My 4age 20V is operating way much too wealthy and provides black smoke in the exhaust. What i also found is actually a vibration at 3/4 throttle to WOT with about just about every RPM. Would not sound flywheel related imo, even though i had that challenge on other vehicles https://jdm-toyota-4a-ge73828.aboutyoublog.com/30079487/4age-20v-itbs-can-be-fun-for-anyone